In recent years, interest in providing light rail-type mass transit in urban and suburban areas, between adjacent pairs of cities, between cities and satellite service facilities such as outlying airports, sports stadia and the like has increased.
Often the feasibility of providing or extending such a transit system fundamentally hinges on cost.
Although some cities, such as San Francisco, Calif., Washington, D.C. and Baltimore, Md. were successful in initiating construction of their light rail urban mass transit systems at a time when a combination of cost factors worked in their favor, those same conjunctions of favorable factors do not presently exist: federal government funding assistance is not so forthcoming, energy prices are at least temporarily in decline, right of way land acquisition costs and construction costs have risen, and car fabrication plants have closed down domestic production lines.
Yet the need of many for convenient light rail-type mass transit goes unmet. It is clear that if more of such mass transit systems are to be built, some innovations are needed.